Uch-L1, an ubiquitin hydrolase, is implicated in numerous neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). Specifically, down regulation of Uch-L1 is both characteristic of neurodegenerative disorders and has been shown to decrease synaptic plasticity in normal cells, while an increase in Uch-L1 activity has proven to increase synaptic plasticity and contextual memory learning in mouse models of AD. Taken together these data suggest that elevation of the catalytic activity of Uch-L1 may be an effective approach in the treatment and prevention of neurodegenerative disorders. The overall goal of this proposal is to characterize Uch-L1 via X-ray crystallographic techniques to determine binding regions that may accommodate binding of a pharmacological chaperone that will increase levels of the activity of Uch-L1 in brain tissue by stabilization of the catalytically active conformation of Uch-L1, where a pharmacological chaperone is small molecule that [unreadable] binds and stabilizes a protein and, consequently, increase cellular abundance and activity. During the [unreadable] course of the two specific aims I will (1) identify non-catalytic binding sites on Uch-l_1 that are capable of binding small, drug-like molecules using an x-ray crystallography technique, specifically the multiple solvent crystal structure (MSCS) method; (2) characterize the structural effects of a single point mutation that is known to increase the catalytic hydrolase activity of Uch-L1 in order to develop a chaperone that would mimic the effects of the mutant. The multiple solvent crystal structures (MSCS) method developed in the Petsko-Ringe lab involves the x-ray crystallographic analysis of enzymes soaked in various solvents. Ligand binding sites are determined by examination of regions of the protein surface where multiple types of solvent molecules bind with high frequency. In the first specific aim the MSCS approach will be employed to identify non-catalytic binding sites of Uch-L1 that, based on their interactions with solvent molecules, will likely be able to bind drug-like molecules. [unreadable] [unreadable] [unreadable]